ABSTRACT: We are requesting funds to replace an aged MoFlo Legacy in poor working state with a MoFlo Astrios EQ Cell Sorter at the Boston University Flow Cytometry Core facility. The BU Flow Core, located on Medical Campus, provides services to more than 90 laboratories with over 180 individual users of our instruments and consulting services. Also, the Flow Core houses the only two cell sorters (a FACSARIA and a MoFlo Legacy) on all the BU campuses. The facility has a large demand for cell sorting that to date is not adequately met; there is an obvious scheduling bottleneck with users often reserving the sorting instruments weeks in advance. To help meet the cell sorting demand, we employ an evening/weekend cell sorter. Our MoFlo Legacy, manufactured in 2001, is a five-color instrument in an aged and dilapidated state, frequently experiencing downtime due to mechanical failures. As Beckman Coulter stopped servicing the MoFlo Legacy in 2013, technical help is non- existent and parts are difficult to acquire, available only on the `used' aftermarket. Brian Tilton, our Director of Cell Sorting, serviced MoFlo instruments in a previous position and therefore his unique skill set has allowed the instrument to remain mostly functional to date. Two features of this instrument that are not present on FACSARIA include `jet-in-air' sorting and a yellow-green laser and both are absolutely required by many of our users. For example, members of BU's Center for Regenerative Medicine (CReM) are heavily dependent on cell sorting for their basic research needs and often require jet-in-air sorting and/or the 560nm laser for their sorts. The CReM and other research groups have experienced significant financial and experimental losses in the last two years due to unreliability of our MoFlo Legacy. Thus, users that specifically require our MoFlo for their research are enduring experimental losses. The MoFlo Astrios we seek to purchase is a jet-in-air sorter and the laser configuration we request will allow simultaneous 18-color detection from 5 lasers including a yellow- green laser (560nm). Acquisition of a MoFlo Astrios will allow thriving research programs in stem cell biology, immunology, infectious diseases, obesity, cardiovascular disease, cancer, and others to continue to expand. When considering the particular cell sorting needs and the growth potential of the Boston University research community, we conclude that a MoFlo Astrios EQ High Speed Cell Sorter is the ideal instrument to replace our aged MoFlo Legacy.